U.S. patent number 5,957,941 [Application Number 08/721,433] was granted by the patent office on 1999-09-28 for catheter system and drive assembly thereof.
This patent grant is currently assigned to Boston Scientific Corporation. Invention is credited to John H. Ream.
United States Patent |
5,957,941 |
Ream |
September 28, 1999 |
Catheter system and drive assembly thereof
Abstract
A system (2) includes broadly a catheter assembly (6) and a
drive assembly (4). The catheter assembly includes a hollow sheath
(20) housing a connecting element, typically a drive cable (22),
with an operative element, such as a transducer (24), towards its
distal end (26). The drive assembly is adapted to move the
connecting element longitudinally within the hollow sheath. The
drive assembly includes a main body (8) to which a proximal
assembly, such as a rotary drive assembly (16), connected to the
proximal end (28) of the connecting element, is mounted for
longitudinal movement along the main body. The main body also has
an anchor element (32) which is used to secure the sheath to the
main body. A longitudinal drive motor (40) is carried by the main
body and drives the proximal assembly along the main body.
Inventors: |
Ream; John H. (San Jose,
CA) |
Assignee: |
Boston Scientific Corporation
(Natick, MA)
|
Family
ID: |
24897979 |
Appl.
No.: |
08/721,433 |
Filed: |
September 27, 1996 |
Current U.S.
Class: |
606/159; 600/443;
606/2; 606/32 |
Current CPC
Class: |
A61B
8/12 (20130101); A61B 8/4461 (20130101); A61B
8/4209 (20130101); A61B 5/0084 (20130101); A61B
5/0066 (20130101) |
Current International
Class: |
A61B
8/12 (20060101); A61B 5/00 (20060101); A61B
017/22 () |
Field of
Search: |
;604/95,159 ;128/DIG.1
;606/1,108,159,2,32 ;600/443 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0244058 |
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Nov 1987 |
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EP |
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0266858 |
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May 1988 |
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0626152 |
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EP |
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2543817 |
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Oct 1984 |
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FR |
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4344312 |
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Jul 1994 |
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DE |
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90/01300 |
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Feb 1990 |
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WO |
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91/15154 |
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Oct 1991 |
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WO |
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92/19930 |
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Nov 1992 |
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WO |
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93/16642 |
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Sep 1993 |
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WO |
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94/00052 |
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Jan 1994 |
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WO |
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94/11038 |
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May 1994 |
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WO |
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WO 94/00052 |
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Jun 1994 |
|
WO |
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97/32182 |
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Sep 1997 |
|
WO |
|
Other References
Brochure: ClearView Ultra.TM. System / UltraCross.TM. Catheters (in
Existence at least as of Sep. 26, 1996). .
Jerome H. Siegel, MD et al., Endoscopic Retrograde
Cholangiopancreatography, Technique, Diagnosis, and Therapy, pp. 5
and 400, Raven Press, New York. .
Joseph E. Geenen, MD et al., Techniques in Therapeutic Endoscopy,
Second Edition, pp. 1.14, 3.6, 7.4, 8.20, and 10.7, Gower Medical
Publishing, New York:London..
|
Primary Examiner: Dawson; Glenn K.
Attorney, Agent or Firm: Townsend and Townsend and Crew
LLP
Claims
What is claimed is:
1. A catheter system comprising:
a catheter assembly comprising a hollow sheath having proximal and
distal ends, a flexible connecting element housed within the hollow
sheath and having proximal and distal ends, an operative element
mounted to the connecting element and a proximal end assembly
coupled to the proximal end of the connecting element;
the sheath comprising a distal, main portion and a proximal,
telescoping portion, the proximal portion slidable within the main
portion; and
a drive assembly comprising:
a main body;
said main body comprising a sheath anchor element secured to said
main portion of said sheath;
a longitudinal drive motor carried by said main body; and
a longitudinal drive train drivingly coupling the longitudinal
drive motor to the proximal end assembly to drive at least a
portion of the proximal end assembly longitudinally to move the
connecting element longitudinally within the main portion of said
sheath.
2. The system according to claim 1 wherein said drive train
comprises a drive belt driven by the longitudinal drive motor and a
coupler coupling the drive belt to the proximal end assembly.
3. The system according to claim 1 further comprising a support leg
extending from said main body.
4. The system according to claim 3 wherein said support leg is an
adjustable position support leg.
5. The system according to claim 1 further comprising first and
second support legs.
6. The system according to claim 5 wherein said support legs are
adjustable support legs.
7. The system according to claim 6 wherein said adjustable support
legs are adjustable position support legs.
8. The system according to claim 1 further comprising a power cord,
electrically coupled to the longitudinal drive motor, extending
from the main body.
9. The system according to claim 1 further comprising a flexible
electrical connection electrically coupling the proximal end
assembly and the main body.
10. The system according to claim 9 wherein said flexible
electrical connection comprises a flat conductor cable.
11. The system according to claim 1 further comprising a control
panel carried by the main body and electrically coupled to the
longitudinal drive motor.
12. The system according to claim 11 wherein said control panel
contains a control element and an indicator.
13. The system according to claim 1 wherein the proximal end
assembly comprises a rotary drive assembly.
14. The system according to claim 1 wherein the flexible connecting
element comprises a fiberoptic fiber.
15. The system according to claim 14 further comprising a bundle of
said fiber optic fibers.
16. The system according to claim 1 wherein the operative element
comprises a lens.
17. The system according to claim 1 wherein said connecting element
and said operative element constitute a portion of an optical
coherence tomography probe.
18. The system according to claim 1 wherein the operative element
is selected from a group comprising rotatable ultrasound
transducers, phased array ultrasound transducers, fiberoptic
devices, optical coherence tomography devices, arterectomy cutters,
laser ablation devices and RF energy ablation devices.
19. A catheter system comprising:
a catheter assembly comprising a hollow sheath having proximal and
distal ends, a flexible drive element housed within the hollow
sheath and having proximal and distal ends, an operative element
mounted to the distal end of the drive element;
the sheath comprising a distal, main portion and a proximal,
telescoping portion, the proximal portion slidable within the main
portion; and
a drive assembly comprising:
a main body;
a rotary drive assembly mounted to the main body;
said rotary drive assembly comprising a rotary drive motor coupled
to the proximal end of the drive element;
said main body comprising a sheath anchor element secured to said
main portion of said sheath;
a longitudinal drive motor carried by said main body; and
a longitudinal drive train drivingly coupling the longitudinal
drive motor to the rotary drive assembly to drive the rotary drive
assembly longitudinally along the main body, whereby the drive
element is moved longitudinally within the main portion of said
sheath.
20. The system according to claim 19 further comprising first and
second adjustable position support legs extending from said main
body.
21. The system according to claim 19 further comprising:
a printed circuit board housed within the main body and
electrically coupled to the rotary and longitudinal drive
motors;
a control panel carried by the main body and electrically coupled
to the printed circuit board;
a power cord, electrically coupled to the printed circuit board,
extending from the main body; and
a flexible electrical connection movably electrically coupling the
rotary drive motor and the printed circuit board.
22. The system according to claim 19 wherein the operative element
is selected from a group comprising rotatable ultrasound
transducers, phased array ultrasound transducers, fiberoptic
devices, optical coherence tomography devices, arterectomy cutters,
laser ablation devices and RF energy ablation devices.
23. A catheter system comprising:
a catheter assembly comprising a hollow sheath having a proximal
end, a flexible connecting element housed within the hollow sheath
and having proximal and distal ends, an operative element mounted
to the connecting element and a proximal end assembly coupled to
the proximal end of the connecting element;
a drive assembly comprising:
a main body;
said main body comprising a sheath anchor element secured to said
sheath;
a longitudinal drive motor carried by said main body; and
a longitudinal drive train drivingly coupling the longitudinal
drive motor to the proximal end assembly to drive at least a
portion of the proximal end assembly longitudinally to move the
connecting element longitudinally within the sheath;
wherein the drive train comprises a drive belt driven by the
longitudinal drive motor and a clutched coupler coupling the drive
belt to the proximal end assembly.
24. The system according to claim 23 wherein said clutched coupler
comprises user-operated clutch actuator which allows a user to
disengaged said clutch coupler from said drive belt to permit the
proximal end assembly to be manually repositioned.
25. A catheter system comprising:
a catheter assembly comprising a hollow sheath having a proximal
end, a flexible connecting element housed within the hollow sheath
and having proximal and distal ends, an operative element mounted
to the connecting element and a proximal end assembly coupled to
the proximal end of the connecting element;
a drive assembly comprising:
a main body;
said main body comprising a sheath anchor element secured to said
sheath;
a longitudinal drive motor carried by said main body; and
a longitudinal drive train drivingly coupling the longitudinal
drive motor to the proximal end assembly to drive at least a
portion of the proximal end assembly longitudinally to move the
connecting element longitudinally within the sheath;
wherein said drive train comprises a user-operated clutch allowing
a user to manually disengage the proximal end assembly from the
longitudinal drive motor.
26. The system according to claim 25 wherein said clutch is carried
by the proximal end assembly to move with the proximal end assembly
between first and second positions.
27. The system according to claim 26 wherein said clutch comprises
a rotatable clutch handle.
28. A catheter system comprising:
a catheter assembly comprising a hollow sheath having a proximal
end, a flexible drive element housed within the hollow sheath and
having proximal and distal ends, and an operative element mounted
to the distal end of the drive element; and
a drive assembly comprising:
a main body;
a rotary drive assembly mounted to the main body;
said rotary drive assembly comprising a rotary drive motor coupled
to the proximal end of the drive element;
said main body comprising a sheath anchor element secured to said
sheath;
a longitudinal drive motor carried by said main body; and
a longitudinal drive train drivingly coupling the longitudinal
drive motor to the rotary drive assembly to drive the rotary drive
assembly longitudinally along the main body, whereby the drive
element is moved longitudinally within the sheath;
wherein said drive train comprises a drive belt driven by the
longitudinal drive motor and a clutched coupler coupling the drive
belt to the rotary drive assembly, said clutched coupler comprising
user-operated clutch actuator which allows a user to disengage said
clutch coupler from said drive belt to permit the rotary drive
assembly to be manually repositioned.
29. A catheter system comprising:
a catheter assembly comprising a hollow sheath having a proximal
end, a flexible drive element housed within the hollow sheath and
having proximal and distal ends, and an operative element mounted
to the distal end of the drive element; and
a drive assembly comprising:
a main body;
a rotary drive assembly mounted to the main body;
said rotary drive assembly comprising a rotary drive motor coupled
to the proximal end of the drive element;
said main body comprising a sheath anchor element secured to said
sheath;
a longitudinal drive motor carried by said main body; and
a longitudinal drive train drivingly coupling the longitudinal
drive motor to the rotary drive assembly to drive the rotary drive
assembly longitudinally along the main body, whereby the drive
element is moved longitudinally within the sheath;
wherein said drive train comprises a user-operated clutch allowing
a user to manually disengage the rotary drive assembly from the
longitudinal drive motor, said clutch being carried by the rotary
drive assembly to move with the rotary drive assembly between first
and second positions.
30. A catheter system drive assembly comprising:
a main body;
a rotary drive assembly mounted to the main body;
said rotary drive assembly comprising a rotary drive motor
coupleable to a catheter drive element;
said main body comprising a catheter sheath anchor element;
a longitudinal drive motor carried by said main body; and
a longitudinal drive train drivingly coupling the longitudinal
drive motor to the rotary drive assembly to drive the rotary drive
assembly longitudinally along the main body;
wherein said drive train comprises a drive belt driven by the
longitudinal drive motor and a coupler coupling the drive belt to
the rotary drive assembly.
31. The drive assembly according to claim 30 wherein said coupler
is a clutched coupler.
32. The drive assembly according to claim 31 wherein said clutched
coupler comprises user-operated clutch actuator which allows a user
to disengaged said clutch coupler from said drive belt to permit
the rotary drive assembly to be manually repositioned.
33. A catheter system drive assembly comprising:
a main body;
a rotary drive assembly mounted to the main body;
said rotary drive assembly comprising a rotary drive motor
coupleable to a catheter drive element;
said main body comprising a catheter sheath anchor element;
a longitudinal drive motor carried by said main body; and
a longitudinal drive train drivingly coupling the longitudinal
drive motor to the rotary drive assembly to drive the rotary drive
assembly longitudinally along the main body;
wherein said drive train comprises a user-operated clutch allowing
a user to manually disengage the rotary drive assembly from the
longitudinal drive motor.
34. The drive assembly according to claim 33 wherein said clutch is
carried by the rotary drive assembly to move with the rotary drive
assembly between first and second positions.
35. The drive assembly according to claim 34 wherein said clutch
comprises a rotatable clutch handle.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to intraluminal imaging.
More particularly, a medical imaging system is provided which
permits the controlled longitudinal movement of an operative
element, such as a rotatable transducer.
Arteriosclerosis, also known as atherosclerosis, is a common human
ailment arising from the deposition of fatty-like substances,
referred to as atheromas or plaque, on the walls of blood vessels.
Such deposits occur in both peripheral blood vessels which feed the
limbs of the body and the coronary vessels which feed the heart.
When the deposits accumulate in localized regions of a blood
vessel, stenosis, or narrowing of the vascular channel, occurs.
Blood flow is restricted and the person's health is at serious
risk.
Numerous approaches for reducing and removing such vascular
deposits have been proposed, including balloon angioplasty where a
balloon-tipped catheter is used to dilate a region of atheroma or
other devices which are pushed or pulled across a lesion such as,
atherectomy where a blade or cutting bit is used to sever and
remove the atheroma, spark gap reduction in which an electrical
spark burns through the plaque, laser angioplasty where laser
energy is used to ablate at least a portion of the atheroma, and
opening of vessels through the use of stents.
A major difficulty in using such devices is obtaining images of and
information on the region of the blood vessel to be treated. To
overcome this difficulty, several techniques have been proposed for
intraluminal imaging of vascular vessels. Catheters incorporating
ultrasonic transducers for imaging are disclosed in U.S. Pat. Nos.
4,794,931; 5,000,185; 5,049,130; and 5,024,234. These catheters
scan in a plane normal to the catheter axis.
Generally deposits extend some longitudinal distance along the
length of a vessel. To view different portions of the deposit a
physician typically moves the transducer along the vessel, for
example, by pushing or pulling the catheter.
Imaging using computer-assisted reconstruction algorithms enables
physicians to view a representation of the patient's interior
intravascular structures in two or three dimensions (i.e.,
so-called three-dimensional or longitudinal view reconstruction).
In this connection, image reconstruction algorithms typically
employ data-averaging techniques which assume that the
intravascular structure between an adjacent pair of data samples
will simply be an average of each such data sample. Thus, the
algorithms use graphical "fill in" techniques to depict a section
of a patient's vascular system under investigation. Of course, if
data samples are not sufficiently closely spaced, then lesions
and/or other vessel abnormalities may in fact remain undetected
(i.e., since they might lie between a pair of data samples and
thereby be "masked" by the image reconstruction algorithms
mentioned previously).
Even with the most skilled physician, it is practically impossible
manually to exercise constant rate longitudinal translation of an
imaging device (which thereby provides for a precisely known
separation distance between adjacent data samples). In addition,
with manual translation, the physician must manipulate the
translation device while observing the conventional two-dimensional
sectional images. It is also difficult to manually exercise
constant rate longitudinal translation of a work-performing element
such an an artherectomy cutter or RF ablation element. This
division of the physician's attention and difficulty in providing a
sufficiently slow constant translation rate can result in some
diagnostic information being missed. To minimize the risk that
diagnostic information is missed, it is necessary to lengthen the
imaging scan time which may be stressful to the patient.
U.S. Pat. No. 5,485,486 discloses an ultrasound imaging transducer
which is capable of being translated longitudinally within a
section of a patient's vascular system at a precise constant rate
through the use of a longitudinal translation assembly. The
longitudinal translation assembly causes the entire rotary drive
assembly to provide the desired longitudinal movement of the
transducer. Such an ability enables a series of precisely separated
data samples to be obtained thereby minimizing (if not eliminating)
distorted and/or inaccurate reconstructions of the ultrasonically
scanned vessel section (i.e., since a greater number of more
closely spaced data samples can reliably be obtained). Also, such
an assembly can be operated in a "hands-off" manner which allows
the physician to devote his or her attention entirely to the
real-time images with the assurance that all sections of the vessel
are displayed. While such a longitudinal translation assembly can
work well, it is relatively large, bulky and heavy; it is
expensive; and it is cumbersome to set up, in part because the
rotary drive and longitudinal translation assemblies are wrapped in
separate sterile drapes (plastic bags) for sterility.
SUMMARY OF THE INVENTION
The present invention is directed to a catheter system and drive
assembly thereof which provides for controlled longitudinal
movement of an operative element, such as an ultrasound transducer,
within a catheter sheath. The assembly can be totally or almost
totally self-contained, light in weight, and simple to set up and
use.
The system includes broadly a catheter assembly and a longitudinal
drive assembly. The catheter assembly comprises a hollow sheath
housing an elongate, flexible connecting element with an operative
element at or near its distal end, and a proximal end assembly at
the proximal end of the connecting element. The connecting element
can be a drive cable and the proximal end assembly can be a rotary
driver for rotating the connecting element about the longitudinal
axis. Lines to and from the operative element, such as power and
signal lines, can extend along the connecting element. The drive
assembly is adapted to move the connecting element longitudinally
within the hollow sheath. In one embodiment this controlled
longitudinal movement permits creation of three-dimensional
vascular images.
The drive assembly includes a main body to which the proximal
assembly is mounted for longitudinal movement along the main body.
The main body includes an anchor element used to secure the sheath
to the main body. A longitudinal drive motor is carried by the main
body and drives a longitudinal drive train coupling the
longitudinal drive motor and the proximal assembly.
In one embodiment the drive train includes a drive belt coupled to
the proximal assembly by a user-actuated clutched coupler. The
clutched coupler preferably includes a clutch handle which is
supported by and moves with the proximal assembly. Using a clutch
permits the user to disengage the proximal assembly from the
longitudinal drive train at any position along the path of
longitudinal movement of the proximal assembly permitting manual
repositioning of the proximal assembly as desired.
The invention also preferably includes one or more adjustable legs
extending from the main body to help support the system comfortably
on, typically, the user's leg. The legs may be adjustable in their
angular orientation, configuration and/or length. This aspect is
important since it permits the physician to devote full attention
to the operative procedure instead of splitting the physician's
concentration due to a need to hold or stabilize the proximal
assembly.
Another advantage of the invention is present when the proximal
assembly is a rotary drive assembly. The rotary drive assembly need
include only those components necessary to be moved along with the
rotary drive motor. That is, the longitudinal drive motor, printed
circuit board, control panel, and other such components need not be
part of the rotary drive assembly so that the rotary drive assembly
can be lighter in weight than would otherwise be necessary. The
lighter weight means that the longitudinal drive motor can be
smaller and the drive train can be simpler and lighter in
construction than would be required if the rotary drive assembly
contained additional components. This helps to reduce the weight
and cost of the entire assembly.
A further advantage of the invention is that with the exception of
the catheter assembly and a power/data cord (when needed),
everything else is part of the drive assembly. This construction
also helps to eliminate the practical problems associated with
having parts of the drive assembly be external of the main housing
or body, such as occurs when one or both of rotary drive and
longitudinal drive motors are separate from the main body. For
example, this permits a single sterile drape (typically a plastic
bag) to be used to cover the entire drive assembly and a length of
the any power/data cord. When the drive assembly provides for both
rotary and longitudinal movement of the operative element, such
drive assembly is as convenient to use as drive assemblies that
only rotate the operative element but do not provide for
controlled, automatic longitudinal movement for the operative
element.
The disclosed embodiment shows the use of a rotatable ultrasound
transducer as the operative element. Other image devices could be
used as the operative element, such as phased array ultrasound
transducers disclosed in U.S. Pat. Nos. 4,841,977 and 4,917,097,
optical coherence tomography optical devices disclosed in U.S. Pat.
No. 5,321,501 and other fiberoptic visualization devices. The
operative element could also be a work-performing device, such as
an artherectomy or other cutter device, a laser ablation device, an
RF energy ablation device and other ablation energy devices.
Likewise, in the disclosed embodiment the proximal end assembly is
a rotary drive assembly. However, the invention can be practiced
with proximal end assemblies which do not rotate the connecting
element. For example proximal end assemblies designed for use with
the above-mentioned operative elements could also be used.
Other features and advantages of the invention will appear from the
following description in which the preferred embodiment has been
set forth in detail in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 1A are overall views showing a vascular imaging system
with the drive assembly in a partially collapsed condition in FIG.
1 and in an extended condition in FIG. 1A;
FIG. 2 is an exploded isometric view of the drive assembly of FIG.
1;
FIGS. 3 and 3A are simplified cross-sectional views of the system
of FIGS. 1 and 1A illustrating the movement of the drive cable and
transducer as the rotary drive assembly moves from the position of
FIGS. 1 and 3 to the position of FIGS. 1A and 3A;
FIG. 4 shows the system of FIG. 1 in use on a patient resting on a
support surface;
FIG. 4A is an enlarged view of the system of FIG. 4;
FIGS. 5, 6 and 7 are simplified cross-sectional views of three
different types of optical coherence tomography probes which can be
utilized in practicing the present invention; and
FIG. 8 is a schematic illustration showing the longitudinal drive
motor of FIG. 2 housed within the rotary drive housing of FIG.
2.
DESCRIPTION OF A PREFERRED EMBODIMENT
FIGS. 1 and 1A illustrate one embodiment of the invention in which
a vascular imaging system 2 is shown in partially collapsed and
extended conditions, respectively. Vascular imaging system 2
includes broadly a drive assembly 4 and a catheter assembly 6.
Assembly 2 is used with an instrument 7, see FIG. 4, which contains
all necessary electronics for data interpretation and signal
generation, keyboard, monitor, and so forth. Instrument 7 is not
part of the invention and thus will not be described in detail.
Drive assembly 4 includes a main body 8 having a generally open
first part 10 and a closed second part 12. First part 10 partially
houses or cradles the housing 14 of a rotary drive assembly 16. See
also FIG. 2. Catheter assembly 6 is mounted to the distal end 18 of
housing 14 by a proximal end adapter 19.
As seen in FIGS. 3 and 3A, catheter assembly 6 comprises a hollow
sheath 20 defining a longitudinal axis 21 and through which a drive
cable 22 extends. Sheath 20 includes a reduced diameter,
telescoping poriton 23 which fits within a main sheath portion 25
at one end and extends from distal end 18 of housing 14 at the
other. A drive cable 22 (connecting element) has a transducer 24
(operative element), typically an ultrasound transducer, at its
distal end 26. The proximal end 28 of drive cable 22 is coupled to
a rotary drive motor 30 mounted within housing 14. First part 10
also includes a stationary anchor post 32 adapted to clip onto an
anchor post adapter 34 surrounding and secured to the proximal end
of main portion 25 of sheath 20. Adapter 34 is used to permit a
secure, non-slip connection between anchor post 32 and sheath 20
without collapsing the sheath.
The longitudinal movement of rotary drive assembly 16 in the
direction of arrow 36 (FIG. 3A) from the partially collapsed
condition of FIGS. 1 and 3 to an extended condition shown in FIGS.
1A and 3A is achieved by a longitudinal drive assembly 38 as shown
in FIG. 2. Longitudinal drive assembly 38 includes a longitudinal
drive motor 40 housed within second part 12. Drive motor 40
includes a drive shaft 42 which drives a drive train 44. Drive
train 44 couples drive shaft 42 to housing 14 of rotary drive
assembly 16. Drive train 44 includes a drive belt 46 supported at
either end by pulleys 48, 50, the pulleys being housed within
second part 12. Pulley 48 is directly driven by a drive gear 52,
gear 52 being driven by drive shaft 42. The outer reach 54 of drive
belt 46 extends through a pair of openings 56, 58 formed in second
part 12 (see FIGS. 2 and 4A).
Housing 14 is coupled to outer reach 54 of drive belt 46 through a
clutched coupler 60. Clutched coupler 60, shown schematically in
FIG. 2, can be clamped to or released from outer reach 54 of belt
46 via manipulation of a clutch actuator 62. Clutch actuator 62
includes an elongate clutch rod 64 and a rotatable clutch handle 66
at the proximal end of the clutch rod. With clutched coupler 60
secured to outer reach 54 of drive belt 46, rotary drive assembly
16 moves in unison with drive belt 46 in a longitudinal direction
along longitudinal axis 21.
Housing 14 is maintained adjacent first part 10 by use of
appropriately sized and positioned grooves and extensions formed in
first part 10 and housing 14. Appropriate stops and/or limit
switches can be used to limit the longitudinal movement of assembly
16.
It is desired to minimize the overall length of drive assembly 4.
Therefore, it is preferred that clutch actuator 62 remain adjacent
to housing 14, such as shown in FIG. 1A, or only spaced apart from
housing 14 sufficiently to permit clutch actuator handle 66 to be
grasped by the user when housing 14 is fully supported by first
part 10 as shown in FIG. 1.
Drive assembly 4 is self-contained with the exception of a
power/data cord 80 extending from a strain relief 82, the strain
relief being captured between the upper and lower sections 84, 86
of second part 12 as shown in FIG. 2. Power/data cord 80 is used to
provide power to the system and to transmit data and instructions
to and from system 2. Power/data cord 80 is coupled to a printed
circuit board 88 which contains the necessary control circuitry for
the system. Printed circuit board 88 is housed within second part
12. Printed circuit board 88 is coupled to a control panel 89
extending from first part 10 adjacent to the proximal end of the
first part. Control panel 10 is used to support various start and
stop switches 91, indicator lights 93, and so forth. Placement of
all such switches and indicators in one place at main body 8,
rather than at a location remote from system 2 and the patient,
helps to ensure the physician is not distracted during a
procedure.
Power and control signals are supplied to rotary drive assembly 16
from printed circuit board 88 through a flexible circuit 90,
typically a flat conductor cable. Flexible circuit 90 is coupled to
printed circuit board 88 at one end and to rotary drive assembly 16
at the other, flexible circuit 90 having passed through second part
12 at location 95 (see FIG. 4A). The use of a flexible circuit 90
permits the transmission of power and control signals to and data
signals from rotary drive assembly 16 even though rotary drive
assembly 16 moves along first part 10. Various lines appropriate to
the type of operative element used, such as power, data, control,
fiberoptics, not shown, pass along drive cable 22 and are typically
directly or indirectly coupled to printed circuit board 88 through
assembly 16 and circuit 90.
To reduce the weight of rotary drive assembly 16, and thus the
torque and power requirements for longitudinal drive motor 40,
housing 14 will preferably house only those components that are
necessary to move with the housing. Typically this will include
rotary drive motor 30 and optionally, a rotary encoder, not shown.
Also, patient isolation, to isolate the patient from any high
voltages, would typically be carried within housing 14.
Drive assembly 4 also includes a pair of pivotal, adjustable legs
92, 94 extending from main body 8. Legs 92, 94 pivot generally
parallel to longitudinal axis 21 to permit main body 8 to rest
securely on a patient's leg 96 (see FIGS. 4 and 4A), or other
support structure, such as table 98. Legs 92, 94 are preferably
pivotally mounted to main body with sufficient frictional
resistance to pivoting such that once placed in a position, the
adjustable legs stay in that position for proper support of
assembly 4. Legs 92, 94 may include a high friction material along
their distal edges to help keep drive assembly 4 stable. Legs 92,
94 may also be adjustable in length, articulated along their
lengths or both. The provision of legs 92, 94 permits the physician
to pay full attention to the procedure and not worry about
maintaining drive assembly 4 balanced on the patient's leg, or
elsewhere.
An advantage of the disclosed embodiment of the invention is that
the drive assembly is always set up to perform one or both of
rotary and longitudinal drive functions; no separate setup is
needed to perform the longitudinal drive functions as can occur
with conventional systems.
In use, a sterile drape (typically a plastic bag) is used to
enclose drive assembly 4; main portion 25 of sheath 20 of catheter
assembly 6 passes through the otherwise closed end of the sterile
drape while the end of power/data cord 80 passes through the
opposite end of the sterile drape. Catheter assembly 6 is flushed
with saline to eliminate any air bubbles which may otherwise
interfere with the operation of transducer 24. Proximal end adapter
19 of catheter assembly 6 is then mounted to distal end 18 of
housing 14 of rotary drive assembly 16. With the rotary drive
assembly in a partially (or totally) collapsed or extended
conditions as suggested in FIGS. 1 and 3 or 1A and 3A, anchor post
32 is clipped onto adapter 34 surrounding the proximal end of main
portion 25 of sheath 20. After the distal end of catheter assembly
6 is introduced into the patient through a hemostasis valve 100
(FIG. 4A), and is properly positioned within the patient, drive
assembly 4 is stably positioned, typically on the patient's upper
leg 96, using legs 92, 94. Rotary drive motor 30 and longitudinal
drive motor 40 are then actuated using control panel 89 so that
transducer 24 both rotates about longitudinal axis 21 and is pulled
longitudinally along the longitudinal axis to generate data
sufficient to create a three-dimensional scan or image of the
vessel. At the end of the scan, rotary drive assembly 16 can be
returned to a desired longitudinal position by the manipulation of
clutch actuator handle 66 which temporarily releases clutched
coupler 60 from outer reach 54 of drive belt 46. Once in the
desired position, actuator handle 66 can be released to permit
clutched coupler 60 to reengage outer reach 54 of drive belt 46.
Alternatively, motor 40 can be operated in reverse to return
assembly 16 to the desired position.
The invention can also be used with optical coherence tomography
optical devices which use fiberoptic fibers to create
high-resolution images of biological and other structures. FIG. 5
illustrates an optical probe 101 in schematic form, such structure
being useful for imaging tubular structures such as blood vessels,
the esophagus, or the like. The distal end of an optical fiber 102
is embedded within an inner catheter 104, the inner catheter being
rotatably mounted within an outer catheter 106. The inner and outer
catheters 104, 106 are both typically housed within a guide sheath,
not shown, but corresponding to sheath 20. Outer and inner
catheters 104, 106 extend beyond the open distal end of the guide
sheath to permit unhindered operation of the optical device. Inner
catheter 104 has a lens 108 secured to its outer end. An angled
mirror 110 is mounted to the distal end of inner catheter 104
adjacent to lens 108, the angled mirror extending beyond the distal
end 112 of outer catheter 106. By rotating inner catheter 104 while
simultaneously moving both inner and outer catheters 104, 106
longitudinally, a three-dimensional scan can be obtained of the
vessel wall 114. Note that in FIG. 5 inner and outer catheters 104,
106 and optical fiber 102 can be considered to constitute the
connecting element corresponding to drive cable 22 of the
embodiment discussed above.
FIG. 6 illustrates a probe 116 having a lens 118 at the distal end
of optical fiber 102. Probe 116 also includes a pivotal mirror 120
and a focussing lens 122 which operate to focus a beam 124 to one
or more optical fibers in an optical fiber bundle 126. The output
from fiber bundle 126 passes through a lens 128 and then a lens 130
before being directed to a sample 132. Fiber bundle 126 and outer
catheter 106 constitute a catheter assembly 127. Appropriate
movement of mirror 120 permits sample 132 to be scanned by a beam
134. With the embodiment of FIG. 6, outer catheter 106 can be
positioned within a hollow sheath corresponding to a sheath 20 and
extend from an open distal end of the sheath. Doing so permits
outer catheter 106 to be moved longitudinally within the guide
sheath according to the present invention. Therefore, catheter
assembly 127 corresponds generally to the connecting element which
is moved longitudinally according to the invention.
FIG. 7 illustrates a further probe 136. The distal end of optical
fiber 102 is connected to a spring 138, the spring mounted to the
inner wall of outer catheter 106. Spring 138 rests on and is
vibrated by a piezoelectric transducer 140 which is coupled to a
piezoelectric driver 142 by a cable 144. Cable 144 extends along
the inner wall of outer catheter 106. Energizing transducer 140
causes spring 138 to move causing the transverse movement of the
distal end of optical fiber 102. This causes a light beam 146 to
move along a graded refractive index lens 148 to cause the output
light beam 150 to move or scan across sample 132. As with probe
116, outer catheter 106 could be housed within and extended from
the distal end of a sheath so that outer catheter 106 can be driven
along the longitudinal axis of the outer sheath.
While there are advantages to separating longitudinal drive motor
40 from rotary drive assembly, housing motor 40 within housing 16
would eliminate much of drive train 44. See FIG. 8 which shows
motor 40 driving a drive wheel 154 along first part 10.
All patents referred to above are hereby incorporated by
reference.
Modification and variation can be made to the disclosed embodiment
without departing from the subject of the invention as defined in
the following claims. For example, longitudinal drive assemblies
other than those using a drive belt, such as a linear actuator, a
worm and worm gear, a rack and pinion, could be used. Legs 92, 94
could be dog-legged or curved so to better engage the patient's leg
96. In some situations it may be possible to eliminate portion 23
of sheath 20. Power could be supplied by batteries and
data/instructions could be transmitted using radiofrequency
transmitters and receivers so to make system 4 self-contained.
While particularly adapted for imaging of vascular regions, the
disclosed embodiment of the invention could be modified for
diagnostic and therapeutic procedures in vascular and other body
structures.
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